Updating Kyero Feeds

I have a couple of Agents who have given me a link to their Kyero Feed.
I browse to the files, then save them and then import the saved files and it seems to work fine.

However, when I need to update next month, do I just browse to the same file and repeat the process?
Will it remove deleted properties and will it overwrite current properties and NOT produce duplicates.
Does the name of the file matter when I save it again.

Thanks for any advice.

Mick